For the monitoring of pipelines for leakage losses and for leakage location in these pipelines, it is known in petroleum pipelines to install control stations along the pipelines and to evaluate the flow characteristics detected at those locations, such as flow rate, flow direction, flow noise, fluid pressure, or the like, with reference to the fluid supplied to the lines and removed therefrom and thereafter, upon the detection of a leak, to locate and subsequently eliminate such leak between two such control stations by means of purposeful measuring and locating operations. In case of petroleum or like media deleterious to the environment, monitoring takes place continuously. Evaluation likewise takes place continuously or quasi-continuously (for example in multiplex). Such methods are known, for example, from: "Z. 3R International, 15th year (July 1976) 7:375-381", "Z. TU11 (June 1970) 6:213-215", "Z. Ol-Zeitschrift fur die Mineralolwirtschaft [Oil Magazine for Mineral Oil Economy] (1973):2-6."
To recognize leakage losses and to locate leakages in interconnected pipeline systems such as, in particular, public drinking water supply systems, it is traditionally customary to travel along the pipeline network and investigate the presence of leaks by means of conventional locating methods. Apart from the fact that only large leaks can be detected, in general, by means of the heretofore customary methods while seepage and noiseless leaks in most cases remain undetected, the conventional method has the disadvantage that a specific point of the pipeline system will be investigated only at very large temporal intervals, in most cases once a year, whereas it is possible for a leak to occur at this point directly after investigation, and this leak will be detected only upon the next investigation. Particularly in case of newly laid pipeline systems examined for leakproofness before being placed in operation, this is a grave disadvantage since the investigation of these pipeline systems in most cases is not begun until several years later.
The losses determined in public drinking water supply systems can markedly exceed 10%, especially if areas with non-reconstructed, old buildings are involved, or if the subterranean conditions are problematic from a geological viewpoint. Since the drinking water must be conveyed under considerable expense and frequently requires treatment (e.g. by means of desalination plants or the like), the socioeconomic losses are considerable.
In case one would apply the methods known in petroleum pipelines, requiring very great accuracy, to the examination of interconnected pipeline systems, a very large number of measuring and control stations would have to be provided, since the conventional methods can only be used for the investigation of conduit sections without branching, even taking house connections into account. Moreover evaluation in the conventional methods takes place continuously. Accordingly, the conventional methods are inapplicable in case of interconnected pipeline systems wherein the conduit length between branching and consumer points sometimes amounts to merely a few meters, not only for practical reasons, on the one hand, but also essentially for financial reasons. Moreover the flood of information and data stemming from the various measuring and control stations and coming in a steady flow is practically no longer processable, even by means of a large-capacity computer.
It is thus an object of the invention to provide a method, by means of which leaks in interconnected pipeline systems can be detected at maximum speed and in an economical fashion.